/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.dao.support;

import java.util.Map;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ReflectionUtils;

/**
 * AOP Alliance MethodInterceptor that provides persistence exception translation
 * based on a given PersistenceExceptionTranslator.
 *
 * <p>Delegates to the given {@link PersistenceExceptionTranslator} to translate
 * a RuntimeException thrown into Spring's DataAccessException hierarchy
 * (if appropriate). If the RuntimeException in question is declared on the
 * target method, it is always propagated as-is (with no translation applied).
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see PersistenceExceptionTranslator
 * @since 2.0
 */
public class PersistenceExceptionTranslationInterceptor
        implements MethodInterceptor, BeanFactoryAware, InitializingBean {

    @Nullable
    private volatile PersistenceExceptionTranslator persistenceExceptionTranslator;

    private boolean alwaysTranslate = false;

    @Nullable
    private ListableBeanFactory beanFactory;


    /**
     * Create a new PersistenceExceptionTranslationInterceptor.
     * Needs to be configured with a PersistenceExceptionTranslator afterwards.
     *
     * @see #setPersistenceExceptionTranslator
     */
    public PersistenceExceptionTranslationInterceptor() {
    }

    /**
     * Create a new PersistenceExceptionTranslationInterceptor
     * for the given PersistenceExceptionTranslator.
     *
     * @param pet the PersistenceExceptionTranslator to use
     */
    public PersistenceExceptionTranslationInterceptor(PersistenceExceptionTranslator pet) {
        Assert.notNull(pet, "PersistenceExceptionTranslator must not be null");
        this.persistenceExceptionTranslator = pet;
    }

    /**
     * Create a new PersistenceExceptionTranslationInterceptor, autodetecting
     * PersistenceExceptionTranslators in the given BeanFactory.
     *
     * @param beanFactory the ListableBeanFactory to obtaining all
     * PersistenceExceptionTranslators from
     */
    public PersistenceExceptionTranslationInterceptor(ListableBeanFactory beanFactory) {
        Assert.notNull(beanFactory, "ListableBeanFactory must not be null");
        this.beanFactory = beanFactory;
    }


    /**
     * Specify the PersistenceExceptionTranslator to use.
     * <p>Default is to autodetect all PersistenceExceptionTranslators
     * in the containing BeanFactory, using them in a chain.
     *
     * @see #detectPersistenceExceptionTranslators
     */
    public void setPersistenceExceptionTranslator(PersistenceExceptionTranslator pet) {
        this.persistenceExceptionTranslator = pet;
    }

    /**
     * Specify whether to always translate the exception ("true"), or whether throw the
     * raw exception when declared, i.e. when the originating method signature's exception
     * declarations allow for the raw exception to be thrown ("false").
     * <p>Default is "false". Switch this flag to "true" in order to always translate
     * applicable exceptions, independent from the originating method signature.
     * <p>Note that the originating method does not have to declare the specific exception.
     * Any base class will do as well, even {@code throws Exception}: As long as the
     * originating method does explicitly declare compatible exceptions, the raw exception
     * will be rethrown. If you would like to avoid throwing raw exceptions in any case,
     * switch this flag to "true".
     */
    public void setAlwaysTranslate(boolean alwaysTranslate) {
        this.alwaysTranslate = alwaysTranslate;
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        if (this.persistenceExceptionTranslator == null) {
            // No explicit exception translator specified - perform autodetection.
            if (!(beanFactory instanceof ListableBeanFactory)) {
                throw new IllegalArgumentException(
                        "Cannot use PersistenceExceptionTranslator autodetection without ListableBeanFactory");
            }
            this.beanFactory = (ListableBeanFactory) beanFactory;
        }
    }

    @Override
    public void afterPropertiesSet() {
        if (this.persistenceExceptionTranslator == null && this.beanFactory == null) {
            throw new IllegalArgumentException("Property 'persistenceExceptionTranslator' is required");
        }
    }


    @Override
    public Object invoke(MethodInvocation mi) throws Throwable {
        try {
            return mi.proceed();
        } catch (RuntimeException ex) {
            // Let it throw raw if the type of the exception is on the throws clause of the method.
            if (!this.alwaysTranslate && ReflectionUtils.declaresException(mi.getMethod(), ex.getClass())) {
                throw ex;
            } else {
                PersistenceExceptionTranslator translator = this.persistenceExceptionTranslator;
                if (translator == null) {
                    Assert.state(this.beanFactory != null, "No PersistenceExceptionTranslator set");
                    translator = detectPersistenceExceptionTranslators(this.beanFactory);
                    this.persistenceExceptionTranslator = translator;
                }
                throw DataAccessUtils.translateIfNecessary(ex, translator);
            }
        }
    }

    /**
     * Detect all PersistenceExceptionTranslators in the given BeanFactory.
     *
     * @param beanFactory the ListableBeanFactory to obtaining all
     * PersistenceExceptionTranslators from
     * @return a chained PersistenceExceptionTranslator, combining all
     * PersistenceExceptionTranslators found in the factory
     * @see ChainedPersistenceExceptionTranslator
     */
    protected PersistenceExceptionTranslator detectPersistenceExceptionTranslators(ListableBeanFactory beanFactory) {
        // Find all translators, being careful not to activate FactoryBeans.
        Map<String, PersistenceExceptionTranslator> pets = BeanFactoryUtils.beansOfTypeIncludingAncestors(
                beanFactory, PersistenceExceptionTranslator.class, false, false);
        ChainedPersistenceExceptionTranslator cpet = new ChainedPersistenceExceptionTranslator();
        for (PersistenceExceptionTranslator pet : pets.values()) {
            cpet.addDelegate(pet);
        }
        return cpet;
    }

}
